[c-nsp] GRE fragmentation and ASR9001

Saku Ytti saku at ytti.fi
Wed Aug 12 07:51:20 EDT 2015

On (2015-08-11 12:20 +0200), Mikael Abrahamsson wrote:


> Re-assembly of fragmented packets is typically something that routers do not
> do. As soon as you need to keep state across packets you need a fairly
> differently engineered device.

You need some state during fragmentation as well. I know that JNPR Trio
generation hardware does fragmentation in NPU, but it's not same rate as
normal forwarding there is per-flow limit to the performance (perhaps it does
not scale to multiple PPE?)
>From cisco.com docs I understand that ASR9k would fragment in LC CPU, which
would surprise me.


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